Keats seems to make allusion by using “Lethe-wards” but I could not find the meaning of this reference, what is it?
Yes, as you know the speaker goes into a distressed mental state, and the only tension is that he slips into numbness state as if a person feels after ingesting an opiate. “Lethe-wards” refers and an allusion to a river in Hades, an underworld in Greek mythology. Here the meaning of “lethe” is forgetfulness. Thus, he feels numbness to forgetfulness and in anguish that he wishes for forgetfulness.